A plasma is a thermally highly heated electrically conductive gas which is composed of positive and negative ions, electrons and excited and neutral atoms and molecules.
Various gases, e.g. monatomic argon and/or the diatomic gases hydrogen, nitrogen, oxygen or air are used as a plasma gas. These gases ionize and dissociate by the energy of the plasma arc.
The parameters of the plasma jet can be highly influenced by the design of the nozzle and of the electrode. These parameters of the plasma jet are e.g. the jet diameter, the temperature, the energy density and the flow speed of the gas.
In plasma cutting, the plasma is usually constricted by a nozzle which may be gas-cooled or water-cooled. For this purpose, the nozzle has a nozzle bore through which the plasma jet flows. Energy densities up to 2×106 W/cm2 can thereby be achieved. Temperatures arise in the plasma jet of up to 30,000° C. which allow very high cutting speeds at all electrically conductive materials in combination with the high flow speed of the gas.
Plasma cutting is today an established process for cutting electrically conductive materials, with different gases and gas mixtures being used in dependence on the cutting work.